5
$\begingroup$

I am writing my thesis about 3D modelling, and I found these illustrations in another thesis. I would like to make something similar.

I can already draw the "egg" shapes in Blender, but this "mesh" and the blue and red details are still a mystery to me. For the mesh, I tried the wireframe modifier, but that doesn't seem to be right for many reasons (it has a thickness, and I couldn't find the dotted option).

Obviously a beginner here, not even sure if this was made in Blender. Any tips on how to do it in Blender (or where this could have been drawn) will be welcomed. I'm unfamiliar with the terms, so the nomenclature for the dotted lines and the blue/red/gray areas would also be helpful. Sample1

$\endgroup$
5
  • 3
    $\begingroup$ Hello, Lucas.. welcome. To kick you off in the right direction I would suggest a thorough reading of either the 'Freestyle' or 'Line Art' section of the user manual, and some experimentation. 'Freestyle' might be the route that presents you with less widely distributed settings, since it does not involve the creation of independent geometry. That may be sufficient to answer this, (perhaps too general for Blender SE?) question. $\endgroup$
    – Robin Betts
    Commented Mar 6 at 8:31
  • $\begingroup$ If the above suggestion does work for you, then perhaps this post should be replaced with some more specific questions, when/if you encounter difficulties with it. to help you up that particular learning-curve. See, for example: blender.stackexchange.com/a/156364/35559 .. incomplete from your POV .. but the sort of thing. $\endgroup$
    – Robin Betts
    Commented Mar 6 at 8:36
  • $\begingroup$ Are the blue and red "details" based on equations? $\endgroup$
    – Rick T
    Commented Mar 6 at 9:16
  • $\begingroup$ @RickT No, just a generic area. The image is about contact mechanics. So these painted areas are general contact surfaces. $\endgroup$ Commented Mar 6 at 9:21
  • 1
    $\begingroup$ Hi. Please use a title that matches the content of the question. It should be descriptive but succinct, unique and identifying, summarizing the issue so that anyone searching for a similar problem is likely to find it. Remove anything superfluous, avoid using words like "this", "help with", "issue" or "question about", instead describe what "it" is. Remember, your title is the first thing potential visitors see, answers you get depend heavily on how insightful it is. See What is the problem of asking “How do I do this?" $\endgroup$ Commented Mar 6 at 10:05

3 Answers 3

9
$\begingroup$

Here is way other than freestyle edge to make this kind of illustration. I used a mix of geometry nodes and blender modifiers and got this result

I will link the file at the end of the post

enter image description here

The sphere's dots and outline are made with geometry nodes

The outline is just the sphere slightly offseted with its normals flipped. The dots are the sphere's edges, that I converted into curves and instanced cubes along these curves. The material needs to have backface culling enabled for the outline to work properly

Here is the node setup :

enter image description here

You can also choose to use sharp edges to control where to put the doted lines

enter image description here

For the red part, you can used a plane, subdivide it and project on the mesh target. I also added a solidify modifier so the backface is visible as well and not occluded by the mesh target.

If you use the outline, set the shrinkwrap modifier snap mode to Above Surface and set the offset to the same value you used for the outline. Then, for the solidify modifier, change the offset to 0 and give it a bit of thickness

enter image description here

For the materials, here is what I used

The sphere material:

enter image description here

The black line material :

enter image description here

The red part material :

enter image description here

enter image description here

Here is the file. Please use blender 4.1 or above for it to work properly

$\endgroup$
6
$\begingroup$

Freestyle in Blender is quite complex and (for me at least) a bit frustrating sometimes because you just do not seem to get lines where you want them :D But to give you a quick idea how you can get something similar like your reference:

Slightly simpler things are not that hard to achieve especially when using the option Mark Freestyle Edge in Edit Mode. For the following example I used three different Freestyle Line Sets, one for the thick external contour, one for the dashed lines of the visible wireframe edges and the last for the thinner, fainter dashed lines of the hidden wireframe:

freestyle wireframe

The material has some alpha transparency to get a bit of that semi-transparent look of your reference. Note however that even the hidden dashed lines will always be overlaid, the material transparency is not necessary for them to be visible.

Also note, although there is a setting where you can have lines on material boundaries, it is not possible to get black outlines along these painted color patches. Freestyle does not detect contours within textures.

For the dashed lines of the wireframe I simply selected all edges in Edit Mode, then Ctrl+E > Mark Freestyle Edge. This way all edges of the base mesh are showing, but all the additional smoothing edges of the Subdivision Surface modifier I put on the object are not visible.

To enable Freestyle, check the option in the Render Properties tab, then you can edit and add line sets in the View Layer Properties tab. The main settings I changed for the three line sets are (by the way lines will be overlaid with the top most line set in front down to the bottom line set in the background):

  1. contour:

    Visibility Type > Visible

    Edge Type > External Contour

    Freestyle Thickness > Base Thickness > 10

  2. dashed line:

    Visibility Type > Visible

    Edge Type > Edge Mark

    Freestyle Strokes > Dashed Line > Dash 1/Gap 1 > 3

    Freestyle Thickness > Base Thickness > 3

  3. dashed line hidden:

    Visibility Type > Hidden

    Edge Type > Edge Mark

    Freestyle Strokes > Dashed Line > Dash 1/Gap 1 > 2

    Freestyle Alpha > Base Transparency > 0.75

    Freestyle Thickness > Base Thickness > 2

The good thing with marking edges as freestyle edges is, no matter how dense a mesh is, you can decide which edges you want to see in a wireframe rendering, like in the example below where all spheres have the same resolution, but different wireframes:

wireframe selection

$\endgroup$
1
  • 1
    $\begingroup$ Really appreciated the detailed steps. $\endgroup$ Commented Mar 6 at 14:00
4
$\begingroup$

You could project an image onto the surface of your object, the image needs to be on transparent background (PNG format) and you'll plug the Alpha output of the Image Texture node into the Alpha input of the Principled BSDF. The inconvenient of this method is that you'll need to change the thickness of the lines if you don't want them to get thinner towards the poles:

enter image description here

$\endgroup$
4
  • $\begingroup$ + 0.5, rounded up :) IMO a good option for the filled ellipse, but some sort of 2D line art better for the wireframe/black line? $\endgroup$
    – Robin Betts
    Commented Mar 6 at 8:56
  • 1
    $\begingroup$ @Robin Betts Sure, it's far from perfect but it may be simpler than freestyle and co $\endgroup$
    – moonboots
    Commented Mar 6 at 9:05
  • $\begingroup$ I think with the introduction of the edge marks in 3.0 it has become quite easy to use Freestyle for basic wireframe rendering... a lot easier then using workarounds with the Wireframe modifier (unless you want geometry on the wireframe) or borders on reset UVs which I used previously. $\endgroup$ Commented Mar 6 at 14:08
  • $\begingroup$ @Gordon Brinkmann oh ok great, i haven't studied it yet $\endgroup$
    – moonboots
    Commented Mar 6 at 14:18

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .